In known plugs of this kind, a sealing mat, or rather matting seal (e.g. a rubber mat or a gel mat) is provided for the protection of the contacting locations of the plug. For this purpose, the contact pins, that preferably have a round cross section, of a mating connector are sealed by the sealing matting applied in the plug in response to the introduction of the mating connector. It is prevented thereby that, for example, water is able to reach the contacting locations from the mating connector via its contact pins, and trigger corrosion there. In order to obtain this sealing mat as a sound sealing element within the meaning of a complete sealing, in spite of contact pins having pierced through it, elastic material (such as rubber) or material that continues to flow (such as gel) is used for the sealing mat, and the sealing or the material that continues to flow is supported using a pressure plate. The sealing matting is clamped in place between the contact carrier's upper part of the plug and the pressure plate which is latched to the upper part of the contact carrier. The electrical contacts of the plug are provided on the contact carrier's lower part, which is connected to the upper part of the contact carrier. Therefore, the plug always has to be equipped with the pressure plate, in order for the sealing mat to be held to the upper part of the contact carrier, that is, in order to be present in the condition in which it can perform its function. From this, there follows an additional material and assembling expenditure in the production of such a plug. Additional tools and assembly steps are also required for the production of the pressure plate, which, together with the assembly, represents a considerable additional expenditure.